The Most Predictive Red Flags to Suspicion of Cardiac Amyloidosis in Patients with Heart Failure with Preserved Ejection Fraction

OBJECTIVE
Cardiac amyloidosis (CA) is a cardiomyopathy characterized by amyloid infiltration in the myocardium. The most common presentation of transthyretin cardiac amyloidosis (TTR-CA) is heart failure with preserved ejection fraction (HFpEF). In our study, we aimed to evaluate the red flags that raise suspicion of CA in HFpEF.

METHODS
Patients diagnosed with HFpEF were included in the study prospectively. All patients were examined cardiac and extra-cardiac for TTR-CA red flag features according to ‘Diagnosis and treatment of cardiac amyloidosis: a position statement of the European Society of Cardiology’. Technetium-99m pyrophosphate (99mTc-PYP) cardiac scintigraphy was performed in HFpEF patients with suspected TTR-CA. And, TTR-CA positive and negative HFpEF patients were compared in terms of red flag features.

RESULTS
In 167 HFpEF patients, 19 (%11.3) patients were diagnosed with TTR-CA. In the TTR-CA group, 17 (89.5%) of the patients were ≥ 65 years old. The presence of ≥3 red flags supported the TTR-CA positive and negative groups (p=0.040). Low voltage and pseudo infarct pattern were more frequent in the group with TTR-CA (p<0.001 and p<0.048). LV global longitudinal strain (LV-GLS) was lower in the TTR-CA positive group (p<0.001). Multivariate analysis revealed that 4 variables 'older age, pseudo infarct pattern, low/decreased QRS voltage and LV-GLS' were strong and independent predictors of TTR-CA. The study showed that these 4 variables were significant at odds ratios (ORs) of 7.8, 6.8, 16.9 and 1.2, respectively.

CONCLUSIONS
In this study, TTR-CA etiology is observed in approximately one in every ten patients with HFpEF. The presence of ≥ 3 red flags increases the possibility of TTR-CA. Older age, pseudo infarct pattern, low/decreased QRS voltage, and reduced LV-GLS were the strongest red flags of TTR-CA in HFpEF patients.